Question: Evaluate the following expression when $c = 10$ and $d = 1$. $9$ $c$ $ + 5$ $d$ $ + 4$
Solution: Substitute $10$ for ${c}$ and $1$ for ${d}$ $ = 9{(10)} + 5{(1)} + 4 $ $ = 90 + 5 + 4 $ $ = 99$